EP2250083B1 - Lift system for an aircraft comprising a main wing and an adjustable slat - Google Patents

Description

The invention relates to a high-lift system for an aircraft having a main wing and a slat which can be adjusted by means of an adjusting device relative to the slat in different adjustment states and which has a device for influencing the flow. With the device for influencing the flow in particular the reduction of the aerodynamic noise is achieved on slats of aircraft.

Documents US 3,363,859 A . EP 0 230 684 A and DE 746 714 C describe a high-lift system for an aircraft with a main wing and an adjustable by means of an adjustment relative to this in various adjustment slats, between which the main wing facing back and the main wing results in a gap, wherein on the back of an air outlet is formed.

The document US 2007/0034746 A1 describes a wing with a main wing, a slat and a trailing edge flap, each having both openings for sucking and openings for blowing air, which are each connected in fluid communication with each other.

In order to be able to deliver sufficient buoyancy force during take-off and landing, the wings of modern aircraft usually have variable high-lift aids (slats and flaps), by the extension of which an optimized optimized for cruising basic geometry at low airspeeds. In the extended state, there is a gap between the front and the main wing, through which the air is accelerated and reaches the suction side with considerable noise emission from the pressure side of the wing. In the flow around the lift-generating surfaces is nowadays a major cause of the noise development of aircraft landing to see.

By Vorlügelumströmung creates a Rezirkulationsgebiet, which is bounded on the one hand by the Vorflügeldruckseite in the form of a groove and on the other hand is separated from the rapid gap flow through a free shear layer. Instabilities of this free shear layer result in the formation of discrete vortex structures, which are then transported continuously along a (notional) separation streamline toward a second stagnation point on the slat bottom. At this point, the flow divides up, and the vortex structures partly enter the recirculation area, but in some cases they accelerate through the gap between the front and main wings. The accelerated movement of the vortices, and in particular their exit from the gap, leads to the emission of sound waves, the sudden impedance jump between solid wall and free flow as it flows off over the vane trailing edge results in the generation of acoustic fluctuations due to hydrodynamic pressure fluctuations. If the vane trailing edge is dull, the interaction of the exiting vortices with a downstream vortex street is to be mentioned as an additional sound source.

A measure for noise reduction may have an adaptation of the geometry of the slat to the shape of the recirculation area to the goal (displacement body, separating surface, bellows). Also means for influencing the free shear layers (brush hair rows) or for damping the sound propagation (acoustic absorber surfaces) may be provided.

One possibility for aerodynamic noise reduction of slats of a commercial aircraft is from the DE 100 19 185 A1 known. In this arrangement, the back profile surface of the slat whose shape is adapted to the outer contour of the main wing, provided with a hollow displacement body (bellows), which can be inflated by means of compressed air from at least one bleed-air line. When the bellows is pressurized with the slat extended, it expands and the size of the adjacent recirculation area decreases. With suitable shaping in the inflated state so the noise-causing vortex formation is reduced at the extended slat.

The DE 199 25 560 A1 describes incorporation of a rigid or flexible interface attached to the supplemental wing, which is disposed along the separation flow line between the backflow and slit flow and extends toward the main wing, thereby impeding momentum exchange across the direction of slit flow and thereby reducing the source noise level of slats.

A similar method for reducing the aerodynamic noise on an additional wing of an aircraft is in the DE 10 2004 056 537 A1 described. The arrangement consists of an n-stable separation surface, which is displaceable with the aid of an actuator device with extended auxiliary wing in the gap and extends there wholly or partially along the separation between the recirculation and slit flow separation stream line, whereby the vortex formation and ultimately the sound radiation can be significantly reduced ,

From the DE 101 57 849 A1 A further arrangement for reducing the aerodynamic noise on a slat of a commercial aircraft is known, which reduces the energy exchange via the resulting on the extended slat shear layers by the use of several, serially arranged along the slat edges brush hairs. The finite flow resistance of this, a separating surface forming brush hairs, softer compensation of the turbulent alternating pressure in the direction of flow and ultimately has a weakening of the acting in the shear layers noise source mechanisms result.

In the document US 6,454,219 describes a slat whose outer skin is perforated on the back or in which an additional noise-absorbing structure is applied to the outer skin of the back of a slat.

In arrangements that provide for the reduction of noise, a positioning of solid structures in the gap between slat and main wing (eg rigid separation surface) exists In general, there is the danger that, in the event of a defect in the kinematic actuation necessary for re-entry, the articulation of the slat against the main wing will be prevented and the aircraft will have to remain in high-lift configuration.

A disadvantage of using additional attachments is seen in a basically increased maintenance. This will be necessary especially in elastic or movable assemblies to prevent possible destruction by aging or fatigue of the material used, the latter may be triggered both by fluctuating aerodynamic loads and by design-related cycling.

For components intended to adapt the slat contour to the shape of the recirculation zone, sudden changes in the flow conditions (e.g., angle of attack) can produce undesirable aerodynamic effects unless the contour is immediately adapted to the changed boundary conditions.

Arrangements aimed at attenuating sound propagation can not reduce the sound radiation to the extent that would theoretically be possible by favorably influencing the sound source mechanism.

The object of the invention is to provide on a high-lift system a measure for reducing the flow noise, which is simple in construction, safe in operation and flexible in terms of changing Anströmbedingungen and in which the aerodynamic properties of the wing largely maintained.

This object is solved by the features of claim 1. Further embodiments are described in the dependent on these subclaims.

According to the invention, in particular, a high-lift system for an aircraft with a main wing and by means of an adjusting device relative to this in various adjustment states adjustable slat, between which the main wing facing back and the main wing results in a gap, the size of which results from the Verstellzustand the slat relative to the main wing provided. Inside the slat, an air duct is formed with at least one inlet and one outlet, wherein the inlet is arranged on the rear side facing the main wing such that air flows from the gap through the inlet into the air duct. It is additionally provided on the back of the slat a section with an absorber material. The absorber material is an absorber material layer integrated into the rear side into which the at least one inlet is integrated.

It can be provided that the mass flow at the inlet on the rear side facing the main wing can be adjusted with a flow adjustment device in order to influence the flow in the gap. The flow adjustment device may in particular have a closure device which can open and close due to the pressure applied to the back. For this purpose, the flow rate adjustment device may have an opening part arranged at the inlet and biased into the closed position of the inlet, which is adjusted such that the opening part moves into an open position at a predetermined first pressure occurring at the back and at a predetermined one at the Rear occurring second pressure goes into the closed position.

Alternatively or additionally, it can be provided that the flow adjustment device is actively controlled.

In general, the flow adjustment device can be arranged within the air duct and / or at the inlets and / or at the outlets.

The inlet may be formed of a plurality of inlet openings. Furthermore, the inlet openings may be arranged in a row along the spanwise direction of the slat. Also, the inlet openings may be arranged in multiple rows along the spanwise direction of the slat. The at least one inlet opening may in particular be a circular opening. In particular, the at least one inlet opening may be an elongate opening.

The slat may have on its rear side facing the main wing a concave curved area as seen from the main wing, in which the at least one inlet is arranged. The slat may have at the location between the front and back at the bottom of the slat extending in the spanwise direction of the slat edge.

The outlet may be a single outlet or may be formed of a plurality of outlet openings. The outlet from the air duct may open into the outer environment of the slat while being located at one or both of the spanwise ends of the slat. Alternatively or additionally, the outlet can open from the air duct into the outer environment of the slat and thereby be arranged at the trailing edge. Furthermore, alternatively or additionally, the outlet can open from the air duct into the outer environment of the slat and be arranged at the edge, which is located on the underside of the slat.

It can also be provided that a connection channel is coupled to the air duct, which opens from the air duct into the interior of the main wing.

For adjusting the flow adjustment between an open and a closed state, it can be provided that the flow adjustment device is functionally coupled to a control device which has a control function for the formation of control signals or control commands for controlling the flow adjustment device.

In this case, the drive device can have an input device with which the drive device can receive sensor and / or system data, and it can be provided that the drive function controls the positioning commands for the opening and determines the closing of the flow adjustment device as a function of the adjustment state of the slat.

In particular, the drive device can have an input device with which the drive device can receive sensor and / or system data, and it can be provided that the drive function the positioning commands for the opening and the closing of the flow adjustment device in response to sensor and / or system data determined.

The drive device can be integrated in the slat.

The input device of the drive device can be set up to receive data from the flight guidance system of the aircraft, and it can be provided, in particular, that the drive function determines the positioning commands for opening and closing the inlet as a function of data of the flight guidance system.

In this case, the data received from the flight guidance system of the aircraft may include the adjustment position of the slat, wherein the control function determines the positioning commands for the opening and the closing of the flow adjustment device as a function of the adjustment position of the slat.

Furthermore, it can be provided that the activation function determines the positioning commands for the flow adjustment device as a function of air data that has been transmitted by the flight guidance system. The air data may describe the angle of attack of the aircraft and / or the speed and / or the attitude of the aircraft.

The drive device of the flow rate adjustment device can have a comparison function, which compares transmitted air data and / or the adjustment position of the slat with a first setpoint value and with a second setpoint value, wherein the activation function is achieved when the first setpoint value is reached in regions Control commands for opening the flow adjustment device and generated at area-wise reaching the second setpoint control command for closing the flow adjustment and transmitted to the flow adjustment.

The control device can be integrated with a computer located in the fuselage of the flight guidance system and the positioning commands are transmitted via a command line to the flow adjustment device.

Furthermore, the high-lift system may comprise at least one pressure sensor, which is arranged on the back of the slat for measuring the static pressure of the air flow and which is functionally connected to the input device for transmitting a measured pressure to the drive function, wherein the drive function is designed such that this Adjusted control signals for the flow adjustment device as a function of the measured pressure.

In particular, the flow rate adjusting device may be realized by one or more valves provided within the air duct for regulating the flow therethrough.

Furthermore, at least one flow drive can be arranged in the air duct, which influences the air mass flow between the inlet and the outlet.

Furthermore, it can be provided that the flow adjustment device is actuated by at least one piezo actuator with which in particular the inlet or several or all inlets and / or the outlet or several or all outlets can be opened and closed. The at least one piezoelectric actuator may be functionally connected via a drive device to the at least one pressure sensor on the rear side of the slat for measuring the static pressure of the air flow in order to adjust the flow rate adjustment device.

The pressure sensor may be arranged at the inlet and / or at the outlet.

In particular, the drive device can have a comparison function with which the pressure at the at least one inlet and at the at least one outlet is compared and determined on the basis of the control signals for the flow adjustment device as a function of the determined pressure difference.

The control device can be integrated with a central computer of the high-lift system, which commands the adjustment of the high-lift flaps.

Furthermore, the drive device can have a table with an assignment of predetermined operational data with desired adjustment positions of the passage adjustment device and a comparison function, with the measured operational data compared with the operational data stored in the comparison table and, in the case of regional matching, the respective assigned setpoint position transmitted to the inlet adjustment.

According to the invention, an aircraft with a high-lift system according to one of the aforementioned embodiments is provided. It can also be provided that the connection channel connected to the air duct opens into the hull.

The invention includes no external attachments on the slat. Additional movable elements are limited to assemblies associated with control of the exhaust mass flow (e.g., valves).

If the pressure difference necessary for suction can be generated by an air-conducting connection between the cavity in the slat and a negative pressure region on the aircraft, the constructive effort and the additional weight are relatively low.

For a hollow slat, the implementation of the noise reduction measure is also conceivable as a retrofit measure.

The arrangement is insensitive to a sudden change in the flow conditions (e.g., change in angle of attack).

If the extraction fails, no negative effect is to be expected apart from an increase in noise emission. In particular, the slat always retracts due to the lack of external attachments.

• Figur 1 einen Teil eines Hauptflügels und einen vor diesem in einem ausgefahrenen Zustand gelegenen Vorflügel im Querschnitt von der Seite gesehen mit einer Darstellung der Strömung zwischen dem Vorflügel und dem Hauptflügel, wenn die erfindungsgemäße Vorrichtung zur Beeinflussung der Strömung nicht vorhanden ist,
• Figur 2 einen Teil eines Hauptflügels und einen Vorflügel in der Stellung der Figur 1 mit einer Darstellung der Strömung zwischen dem Vorflügel und dem Hauptflügel, wenn die erfindungsgemäße Vorrichtung zur Beeinflussung der Strömung vorhanden und aktiviert ist.

Embodiments of the invention will be described with reference to the accompanying figures which show:

• FIG. 1 a part of a main wing and a slat located in front of this in an extended state in cross-section from the side with a representation of the flow between the slat and the main wing, if the inventive device for influencing the flow is not present
• FIG. 2 a part of a main wing and a slat in the position of FIG. 1 with a representation of the flow between the slat and the main wing, when the device according to the invention for influencing the flow is present and activated.

According to the invention, a high-lift system is provided for an aircraft with a main wing and a slat which can be adjusted by means of an adjusting device relative to the slat in different adjustment states. The slat has a back 1 b, which faces the main wing. Between the back 1 b and the main wing 2 results in a gap 5, the size of which results from the Verstellzustand the slat 1 relative to the main wing 2 and thus in particular by the removal of the slat 1 to the main wing 2. In the interior of the slat an air duct 11 is formed with at least one inlet 20 and an outlet. In this case, the inlet 20 is arranged on the main wing facing back 1 b to influence the flow in the gap 5.

The cavity 11 in the slat 1 may be continuous or divided into a plurality of separate single chambers, e.g. to allow a local adjustment of Absaugmassenstroms controlled by different pressure conditions in the individual chambers.

The FIG. 2 schematically shows the structure of a possible embodiment of the arrangement for reducing the aerodynamic noise on a main wing 2 extended slat 1, and their influence on the slat flow around. In the illustrated two-dimensional section through the configuration, it can be seen that the solution for noise reduction according to the invention uses a perforated inner contour on the slat through which the turbulent air is extracted from the recirculation area 9.

For this purpose, the slat may in particular be provided with a cavity which is used as the air duct 11. The inlet 20 at the rear side facing the main wing 1 b is applied in a suitable manner with a negative pressure relative to the pressure in the recirculation 9 to produce a continuous Absaugmassenstrom through the perforation. The sucked air is discharged from the cavity via at least one air line (not shown).

According to the invention, provision can be made in particular for the mass flow drawn off on the back side 1 b facing the main wing to be adjusted with a flow adjustment device in order to influence the flow in the gap 5. The mass flow flowing through the air duct 11 results from the flow conditions at the at least one inlet and at least one outlet, optionally depending on their opening conditions and optionally by a flow drive effective in the air duct 11 or several flow drives effective in the air duct 11.

For this purpose, the flow adjustment device may have a closure device, which automatically due to the voltage applied to the back 1b, ie without active actuation, can open and close. The flow adjusting device can be arranged on at least one inlet, at least one outlet and / or within the air duct.

For this purpose, the flow rate adjusting device may have an opening part arranged at the inlet 20 and biased into the closed position of the inlet, which is adjusted such that the opening part moves into an open position at a predetermined first pressure occurring at the rear side 1b and at a first pressure predetermined occurring at the back of 1 b second pressure goes into the closed position.

Furthermore, the flow adjustment device can be actively controlled. For this purpose, in particular a flow adjustment device can be arranged within the air duct 11 and / or at the inlets.

To explain the operation of the arrangement in detail, is first based FIG. 1 on the sound generation mechanism in the flow around the uninfluenced base configuration. The main wing 2 facing side (inside) of the slat 1 is usually concave shaped to be able to address it in cruise to the nasal contour of the main wing. At the transition from the convex outer side to the concave inner side, a kink arises in the contour 3, which can not follow the rapid flow around the slat. The flow dissolves at this edge and there is a free shear layer 6, which rolls up as a result of disturbances and instabilities to discrete vortex structures 8. The thus continuously generated vortices are transported with the flow along a (fictitious) Trennstromlinie 7 until they are near the Wiederanlegepunktes on the slat base. At this point, the flow is divided, whereby here for simplicity only the flow in a plane is discussed and a possibly existing cross flow in the spanwise direction is neglected. As the stagnation point approaches, the vortices are subjected to shear forces of medium flow and elongated. A portion of the incoming vortex 8 will enter shortly before reaching the stagnation point in the turbulent Rezirkulationsgebiet 9, the continuous rotational movement due to the rapid gap flow constantly is maintained. The turbulence within the recirculation zone in turn destabilizes the free shear layer and stimulates its disintegration into discrete vortex structures. The remaining part of the approach point approaching vortex is transported through the gap 5 between the front and the main wing, experiencing a considerable acceleration and finally exits under interaction with the trailing edge 4 of the slat and there possibly arising, alternating vortex street 10 from this ,

As causes for the considerable sound generation at the slat different effects are to be mentioned. A swelling mechanism is known to be seen in the pressure fluctuations on the profile surfaces caused by wall-like transient whirling motion (surface sources). In addition, the strong acceleration of the vortex during transport through the gap leads directly to sound emission (volume sources). As a significant source of sound is also the sudden impedance jump in the outflow of the vortex on the slat trailing edge to call (edge noise). A vortex street, which possibly arises downstream of this point, constitutes a further sound source, especially as a result of its interaction with eddies emerging from the gap. Farther downstream, eddies ejected through the gap can enter the boundary layer on the main profile and generate additional surface sound there.

To explain the sound-reducing effect of the presented arrangement, it is recommended to first compare the basic configuration ( FIG. 1 ) and modified variant ( FIG. 2 ) to change the flow topology. In both cases, a free shear layer 6 will form between recirculation region 9 and the rapid gap flow, from which discrete vortex structures 8 will eventually form as a result of disturbances and instabilities. Since the boundary layer thickness decreases on the slat inside by the suction, it can be assumed that the free shear layer will be thinner in the affected case. The recirculation area 9 is withdrawn by the exhaust vortex-laden air, so the initial development of the free shear layer 6 will be disturbed by less instabilities than in the uninfluenced case. The combination These effects can lead to the formation of smaller vortex structures and their delayed formation compared to the basic configuration. As in FIG. 1 is indicated by the branching of the separation flow line 7 in the vicinity of the re-application point on the slat inside, divides the vortex flow at this point, in particular the vortex, which does not enter the recirculation 9, but instead are accelerated through the gap 5 and on the Depart the trailing edge of the slat, causing strong sound emission.

This undesirable effect due to the escape of vortices from the gap 5 may be due to the in FIG. 2 shown arrangement partially or completely avoided. For reasons of continuity, the amount of air extracted from the recirculation area 9 must be supplied by the flow around. Since the flow at the lower slat edge 3 detaches geometry-induced, the air can flow to the recirculation area only via a displacement of the separation flow line 7, it excludes compensating edge effects at the span-wide ends of the slat. The displacement of the separation stream line entering through the suction results in an increased transport of vortices from the free shear layer 8 in the direction of the suction slits, whereby at the same time the ejection of vortices through the gap 5 is reduced and thus the noise emission is reduced. The distribution of the vortex structures at the branching point can be controlled via the suction mass flow. Since the thickness of the turbulent shear layer 7 is small in comparison to the fast-flowing gap 5, even with a small ratio of Absaugmassenstrom to Spaltmassenstrom, ie without significant change in the aerodynamic effect, a noise-reducing effect can be achieved. For larger Absaugmassenströmen the complete deflection of all shear layer vertebrae in the recirculation area is conceivable, however, a limitation of Absaugmassenstroms appears useful to limit the aerodynamic influence of the arrangement.

The inlet 20 of a slat may be formed from an inlet opening or from a plurality of inlet openings. The inlet openings may be arranged in a row along the spanwise direction of the slat. Also, the inlet openings be arranged in several rows along the spanwise direction of the slat.

Also, the at least one inlet opening may be a circular opening 21. The at least one inlet opening may be an elongated opening.

According to the invention, a section with an absorber material is additionally provided on the rear side 1b of the slat 1 as an absorber material layer integrated in the slat back, into which the at least one inlet is integrated.

If an air-permeable, possibly porous material is used, it is further conceivable to improve the noise-reducing effect of the arrangement by the combination of suction and a permeable, locally reacting absorber surface. In this way, both sound generation and sound propagation in the sense of noise reduction could be favorably influenced.

The slat can be designed in various ways and in particular also in connection with the arrangement of the inlet and / or the outlet. In this case, the slat on its side facing the main wing back 1 b have seen from the main wing from concave curved area 4, in which the at least one inlet 20 is arranged. Furthermore, the slat 1 at the point between the front 1 a and 1 b back at the lower portion of the slat 1 have a running in the spanwise direction of the slat 1 edge 3.

The outlet may be formed of a plurality of outlet openings. In particular, the outlet can open from the air duct into the outer environment of the slat 1 and thereby be arranged at one or both ends of the slat 1 located in the spanwise direction. Alternatively or additionally, the outlet can open from the air duct into the outer environment of the slat 1 and be arranged at the trailing edge 4.

The outlet can open from the air duct 11 into the outer environment of the slat 1 and be arranged at the edge, which is located at the bottom of the slat.

Also, a connection channel may be coupled to the air duct 11, which opens from the air duct 11 into the interior of the main wing.

According to a further embodiment of the invention, the flow adjustment device may be functionally coupled to a drive device having a drive function for the formation of actuating signals or control commands for controlling the flow adjustment device, with which the flow adjustment are adjusted between an open and a closed state can. The drive device can have an input device with which the drive device can receive sensor and / or system data. In particular, the control function can determine the positioning commands for the opening and the closing of the flow adjustment device as a function of the adjustment state of the slat.

Furthermore, the drive device can have an input device with which the drive device can receive sensor and / or system data, and it can be provided that the drive function controls the positioning commands for opening and closing the flow rate adjustment device as a function of sensor and / or system data determined.

The drive device can be integrated in the slat 1.

The input device of the drive device can be set up to receive data from the flight guidance system of the aircraft. Functionally, the activation function can continue to be designed in such a way that the positioning commands for opening and closing the flow rate adjustment device are determined as a function of data from the flight guidance system.

In this case, the data received from the flight guidance system of the aircraft may in particular include the adjustment position of the slat and the control function may continue to be functionally configured such that the positioning commands for opening and closing the flow adjustment device are determined as a function of the adjustment position of the slat.

Furthermore, it can be provided that the activation function determines the positioning commands for the flow adjustment device as a function of air data that has been transmitted by the flight guidance system. The air data can describe the angle of attack of the aircraft and / or the speed and / or the attitude of the aircraft.

Furthermore, it can be provided that the control device of the flow adjustment device has a comparison function, the transmitted air data and / or the adjustment of the slat compares with a first setpoint and with a second setpoint, the drive function at area reaching the first setpoint control command for opening the Flow adjustment and upon reaching the second setpoint control command for closing the flow adjustment device generated and transmitted to the flow adjustment.

The control device can be integrated with a computer located in the fuselage of the flight guidance system, wherein the control commands are transmitted via a command line to the flow adjustment device.

The high-lift system may comprise at least one pressure sensor arranged on the back 1a of the slat 1 for measuring the static pressure of the air flow. The pressure sensor may be operatively connected to the input device for transmitting a measured pressure to the drive function and the drive function may be designed such that it determines the actuating signals for the flow rate adjustment device as a function of the measured pressure.

In one embodiment of the invention, the flow rate adjustment device may be realized by one or more valves provided within the air duct 11 for regulating the flow therethrough. The valve or valves may be operatively connected to the drive device in accordance with described alternatives for actively moving the valve or valves. Alternatively or additionally, the adjustment of the valve or the valves in the manner described passively and in particular due to the voltage applied to the back of 1 b pressure. The additional provision of a passive adjustment can be advantageous in particular for making available a safety function in the sense of a fail-safe function.

In the mentioned embodiments of the invention, the air mass flow in the air duct 11 can be generated by means of at least one flow drive which influences the air mass flow between the inlet and the outlet, i. generated or supported. The at least one flow drive may be arranged within the air duct 11 between inlet and outlet. The flow drive may be a pump or a propeller. The drive device for the flow drive can be arranged outside of the air duct 11.

According to the invention, the flow adjustment device can also be actuated by at least one piezoactuator.

In this case, the at least one piezoactuator can be structurally integrated in the closure device or opening device for opening or closing the inlet. The flow adjustment device can also be formed from one or more piezoactuators, which are applied to one surface or to two surfaces which extend in the longitudinal direction of the flow adjustment device and lie opposite one another. In this case, the flow adjustment device is designed to be flexible so that correspondingly applied piezoactuators, which are designed for the adjustment modes contraction and elongation, can change the shape and, in particular, the curvature of the flow adjustment device in its longitudinal direction.

The piezoactuators can be formed, for example, in the form of piezoceramic films, thin plates, wafers or fibers, including piezoceramic fibers with interdigital electrodes. Several plate-shaped piezoactuators can also be arranged one above the other in layers in a plurality of discrete layers and assembled into a flat plate-shaped actuator package (as a multilayer structure or in a bimorph design).

In this case, the at least one piezoactuator can be actively activated via a drive device according to the invention, or the piezoactuators can be realized with a passive circuit and make the shape change of the flow rate adjustment device due to a movement thereof, i. amplify and / or continue an initial movement, which can be carried out in the manner described automatically due to pressure differences occurring. The passive circuit can be used without or with a driving device, e.g. be formed as a security function. In this case, the piezoactuators and the coupling circuit are designed such that it is sent at an extension of the same, due to an initial movement in a retraction or extension direction of the flow adjustment control signals to at least a portion of the piezo actuators in order to continue this initially detected adjustment of the flow adjustment device to operate. The piezoactuators may also include a travel range magnifying element, such as a piezoelectric actuator. have a corresponding rod which transforms the deflections of the piezo actuators accordingly.

In particular, it can be provided that the piezo actuator is functionally connected via a drive device to the at least one pressure sensor on the rear side 1a of the slat 1 for measuring the static pressure of the air flow in order to adjust the flow adjustment device.

The at least one pressure sensor may be arranged at the inlet and / or at the outlet.

Furthermore, the drive device can have a comparison function, with which the pressure at the at least one inlet and at least one outlet is compared and determined on the basis of the control signals for the flow adjustment device as a function of the determined pressure difference.

The control device can be integrated with a central computer of the high-lift system, which commands the adjustment of the high-lift flaps.

The control device can have a table with an assignment of predetermined operational data with desired adjustment positions of the inlet adjustment device and a comparison function, with the measured operational data compared with the operational data stored in the comparison table and, in the case of regional matching, the respectively assigned desired positioning position and transmits the inlet adjustment.

reference numeral

1

vane

1a

Front of the slat

1b

Back of the slat

2

main wing

3

Lower edge (of the slat 1)

4

Trailing edge (of the slat 1)

5

gap

6

free shear layer

7

Dividing streamline

8th

vortex structures

9

recirculation

10

vortex street

11

Cavity (slat 1).

Claims (11)

1. High-lift system for an aircraft having a main wing and a slat which can be adjusted into various adjustment states with respect to the main wing by means of an adjustment device, a gap (5) being provided between the rear side (1b) of the slat facing the main wing and the main wing (2), the size of said gap (5) resulting from the adjustment state of the slat (1) with respect to the main wing (2),
   wherein an air conducting duct (11), having at least one air conducting duct inlet (20) and one air conducting duct outlet, is formed in the interior of the slat, wherein the air conducting duct inlet (20) is arranged on the rear side (1b) facing the main wing in such a way that air from the gap (5) flows through the air conducting duct inlet (20) into the air conducting duct (11),
   characterized in that in addition on the rear side (1b) of the slat (1) there is a section with an absorber material as an absorber material layer which is integrated into the slat rear side (1b) and into which the at least one air conducting duct inlet is integrated.
2. High-lift system according to Claim 1, characterized in that the absorber material is an air-permeable material.
3. High-lift system according to one of the preceding claims, characterized in that the absorber material is a porous material.
4. High-lift system according to one of the preceding claims, characterized in that the mass flow at the air conducting duct inlet (20) can be set at the rear side (1b) facing the main wing with a through-flow adjustment device in order to influence the flow in the gap (5).
5. High-lift system according to one of the preceding Claims 1 and 2, characterized in that the through-flow adjustment device has a closure device which can open and close on the basis of the pressure present at the rear side (1b).
6. High-lift system according to Claim 5, characterized in that the mass flow at the air conducting duct inlet (20) can be set at the rear side (1b) facing the main wing with a through-flow adjustment device, and in that the through-flow adjustment device has an open part which is arranged on the air conducting duct inlet (20) and is prestressed into the closed position of the air conducting duct inlet and is set in such a way that the opening part moves into an open position when there is a predetermined first pressure occurring at the rear side (1b) and goes into the closed position when there is a predetermined second pressure occurring at the rear side (1b).
7. High-lift system according to Claim 4, characterized in that the through-flow adjustment device is controlled actively.
8. High-lift system according to Claim 7, characterized in that the through-flow adjustment device is functionally coupled to an actuation device which has an actuation function for forming actuation signals or actuation commands for actuating the through-flow adjustment device, with which actuation signals or actuation commands the through-flow adjustment device can be adjusted between an open state and a closed state, wherein the actuation device has an input device with which the actuation device can receive sensor data and/or system data, and in that the actuation function determines the actuation commands for opening and closing the through-flow adjustment device in dependence on the adjustment state of the slat, or in that the actuation function determines the actuation commands for opening and closing the air conducting duct inlet in dependence on sensor data and/or system data.
9. High-lift system according to Claim 4, characterized in that the through-flow adjustment device is activated by at least one piezoactuator.
10. High-lift system according to one of the preceding claims, characterized in that the slat (1) has, at the location between the front side (1a) and the rear side (1b) in the lower region of the slat (1), an edge (3) running in the spanwise direction of the slat (1).
11. High-lift system according to one of the preceding claims, characterized in that the air conducting duct outlet of the air conducting duct opens into the outer surroundings of the slat (1), and is arranged at one end, or at both ends, located in the spanwise direction, of the slat (1) or on the rear edge (4) of the slat (1) or on the underside of the slat (1).

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